Automatic smoke generator



H. K. TUCK AUTOMATI C SMOKE GENERATOR July 19, 1966 2 Sheets-Sheet 1 Filed June 11, 1964 IMVENTOR HAROLD K. TUCK July 19, 1966 K- TUCK AUTOMATIC SMOKE GENERATOR 2 Sheets-Sheet 2 Filed June 11, 1964 INVENTOQ HAROLD K. TULLH 4mm, gzfipckwm,fl/wmawaio@ United States. Patent 3,261,345 AUTOMATIC SMOKE GENERATOR Harold K. Tuck, Beloit, Wis., assignor to United Industries, Inc., Chicago, Ill., a corporation of Illinois Filed June 11, 1964, Ser. No. 374,421 6 Claims. (Cl. 126-595) This invention relates to improvements in smoke generators in general, and more-particularly is directed to a new and improved feeder assembly particularly adapted for use in a smoke generatorto convey combustible material from .a supply hopper to the burning area or bed within the fire pot, and to maintain the b'ed depth substantially uniform at all times regardless of the rate of burning of the combustible material.

The present invention relies upon maintaining control over the bed depth in order to control the burning and smouldering of combustible material, to obtain maximum smoking while practically eliminating all open flames. For purposes of description, the combustible material will be referred to as damp sawdust however, it is to be understood that combustible materials other than damp sawdust may be equally well suited for smoke generation.

In the present invention, production of wood .smoke is achieved by the use of a regulated forced air supply to support combustion while automatically controlling feed of the damp sawdust to the fir'e pot or bed. The heat from the sawdust which is burning causes the moist sawdust disposed above it to smoulder producing smoke. Suitable means is provided to direct the smoke from the fire pot or bed through a stack for distribution to a smoke house or the like. A new and improved feeder assembly for directing the damp sawdust from a supply hopper to the fire pot or bed of combustible material is provided to automatically maintain the bed at uniform depth regardless of the rate of burning and thereby obtain optimum results by way of total amount of smoke g'enerated when the volume of material burned is considered. The feeder assembly is provided with means which permits ready adjustment of the bed depth to compensate for differences in moisture content in different types of materials used in the production of smoke.

A complete understanding of the more salient features of the present invention will be had upon consideration of the objects to be achieved and a description of the novel structure developed for the achievement of these objectives.

It is an object of this invention to provide a new and improved automatic smoke generator.

It is a further object of this invention to provide continuous and automatically controllable means for the production of smoke for use in smoking various types of food products.

It is a further object of this invention to provide a new and improved feeder assembly for use in an automatic smoke generator to maintain the level of combustible material substantially uniform thereby to promote uniform burning, maximize the production of smoke and minimize flaming of the combustible material.

It is a further object of this invention to provide a feeder assembly for use in an automatic smoke generator which will maintain the bed of combustible material at a substantially uniform pre-s'elected depth to promote the production of smoke for main the smoking of foods such as meat, cheeses, sandwich spreads and the like.

Further and fuller objects will become readily apparent when reference is made to the accompanying drawings wherein:

FIG. 1 is a vertical elevational view in cross section of the automatic smoke generator of the present invention;

3,261,345 Patented Juiy 19, 1966 FIG. 2 is a cross sectional view taken along the lines 2-2 of FIG. 1;

FIG. 3 is a free body perspective view of the feeder assembly with a lower portion of the sawdust supply hopper shown fragmentarily; and

FIG. 4 is a side elevational view of the feeder assembly.

The automatic smoke generator of the present invention is indicated generally by reference character 10 in FIG. 1 and includes an outer annular housing 11 which mounts a supply hopper 12. At the lower or bottom of the portion of the housing 11 is a fire pot indicated generally at 13. A feeder assembly 14 is mounted centrally of the fire pot 13 and directs damp sawdust from the supply hopper 12 to the fire pot 13 causing smoke to be generated which is drawn off through the exhaust stack indicated generally at 15. A drive unit 16 is provide-d at the top of the housing for rotating the feeder assembly to maintain uniform flow of combustible material 31 from the supply hopper 12 to the fire pot 13 as will be described more completely hereinafter.

Referring now to FIGS. 1-4, it can be observed that the supply hopper 12 is mounted at the upper portion of the housing 11 and includes frustoconical wall portions 17 which terminate in an annular flat bottom portion 18 having a central sleeve-like cylindrical opening 19 which leads into the feeder assembly 14.

A drive shaft 20 extends from the drive unit 16 through the supply hopper, central opening 19, and the feeder assembly 14, and is journaled in a suitable bearing 21 provided at the lower or bottom portion of the housing 11. A vane 22 is attached to the shaft 20 within the supply hopper 12 and generally conforms to the contour of the frustoconical wall portion 17. As the shaft 20 is rotated by the drive unit 16 the vane 22 maintains the damp sawdust in the supply hopper agitated so as to be freely flowable to the opening 19 under the influence of gravity. A smaller agitator 23 is positioned in the cylindrical opening 19 to prevent clogging or packing of the sawdust 31 as it flows to the feeder assembly 14.

A slide damper or valve 24 extends into the sleeve- -like cylindrical opening 19 to permit the flow of sawdust 31 from the supply hopper 12 to the feeder assembly to be controlled. The slide damper or valve 24 may be provided with a U-shaped cutaway portion to allow it to be slidably received around the shaft 20 immediately above the vane 23 when moved to the cut off position.

The fire pot 13 is disposed in the lower portion of the housing 11 and is formed with double walls 25 and 26. The walls 25 and 26 are annular in form, closed at one end, and spaced apart to provide an area 27 therebetween to confine water fed through a supply pipe 28. An overfiow pipe 29 at the top of the fire pot 13 maintains the water at uniform level and permits the continuous circulation of cool water throughout the water jacket area 27 around the sides and bottom of the fire pot 13.

A plenum or air supply chamber 29 is provided along the lower peripheral portion of the wall 25 adjacent the bottom of the fire pot 13. A series of orifices or openings 30 are provided in the plenum 29 to promote the uniform distribution of combustion supporting air to the bed of combustible material indicated generally at 31. A blower 32 supplies air through a control valve 33 to the plenum 29 to support combustion in the area immediately adjacent the orifices or air ports 30. The valve 33 may be .a gate valve or the like and serves to permit adjustment of the quantity of air fed from the blower 32 which in turn permits control to be exercised over the rate of combustion of the sawdust 31.

The circulation of water between the walls 25 and 26 maintains the fire pot 13 at reduced temperatures thereby permitting it to be manufactured from relatively light gauge material. Additional benefits are obtained by keeping the combustible material cool to promote good smoking, and cooling the smoke as it leaves the fire pot 13. A hearing housing is formed by a cylindrical sleeve 34 passing through the bottom portion of the fire pot 13 and projects above the base of the fire pot a slight distance. A collar 35 is fixed to the shaft 20 and projects downwardly over the bearing housing 34 to form a labyrinth seal which serves to exclude the foreign material such as ashes and the like from the bearing chamber.

The novel feeder assembly 14 functions to transfer the combustibl material or damp sawdust from the supply hopper 12 to the fire pot 13 and in so doing maintains a generally uniform bed depth relative to the air supply 29. To the attainment of this end, the feeder assembly 14 includes a cylindrical mounting sleeve 36 which is slidably received around the shaft 20 and is clamped thereto by means of a split clamp 37 of conventional design. A rotating or intermediate hopper 38 is carried at the upper end at the mounting sleeve 36 and is of cylindrical form having a flat bottom portion 39 joined to upstanding side wall portion 40. The side wall portion 40 is interrupted as is the bottom 39 in the region of the outer periphery to form an opening 41 leading to a distributor hopper 42.

The hop-per 42 is formed by a pair of radially directed plates 43 and 44 which are closed at their outer ends by an end plate 45. An incline chute 46 leads from the inner marginal edge of the opening 41 to the lower edges of the plates 43 and 44 to form the inner wall of the distributor hopper 42, and serves to direct material ejected from the rotating hopper 38 outwardly to the area of burning. The size of the opening 41 may be readily controlled by an adjustable plate-like valve 47 and under ordinary circumstances once adjusted will not require readjustment.

An arcuate scraper 48 extends from the cylindrical mounting sleeve 36 outwardly along a generally spiral path for attachment to the plate 43. On rotation of the shaft 20, the scraper 48 serves to direct any material falling towardthe center of the fire pot 13 outwardly into the area of combustion, as will be described more completely hereinafter.

The lower marginal edge 49 of the plate 43 is trimmed so as to be generally arcuate between the end plate 45 and the incline chute 46 and merges smoothly with a generally straight edge portion 50 which is inclined toward the central axis of the mounting sleeve 36. Accordingly, as the feeder assembly rotates the cross section of the bed of sawdust 31 will be generally speaking, that of a right triangle wherein the hypotenuse is generally arcuate. The direction of rotation of the feeder assembly is such that the arcuate edge 49 and straight edge portion 50 are leading edges.

The mounting plate 44 is also provided with a trailing edge 51 of arcuate configuration which is disposed slightly below the leading arcuate edge 49. The arcuate edge 51 extends the full length of the lower edge of the mounting plate 44- between the incline chute 46 and the outer closure plate 45. Arcuate edges 4-9 and 51 serve to distribute a generally circular mound of sawdust 31 of consistent or uniform depth as the feeder assembly is rotated. Since the trailing edge 51 is slightly lower than the leading edge 43, it scrapes the surface of the mound of sawdust 31 causing an upward force against the sawdust in the hopper 42 to prevent additional sawdust from being released by the rotating feeder assembly 14. This will become more apparent upon description of the operation of the device.

Referring once again to FIG. 3, a fragmentary portion of the cylindrical opening 19 of the supply hopper 12 is illustrated disposed immediately above the feeder assembly 14. As is apparent in FIGS. 2 and 3, the sleevelike cylindrical opening 19 is provided at its lower marginal edge with a deflecting vane 52 which projects generally tangentially from the sleeve-like cylindrical opening 19 towards the vertical wall of the rotating hopper portion 38 of the feeder assembly 14. As rotation of the feeder assembly 14 occurs, the deflecting vane 52 causes a quantity of sawdust to be scraped or ejected into the opening 41 on each revolution to maintain the rotating hopper filled with sawdust 31 for distribution to the fire bed as will be described below.

The smoke exhaust portion 15 of the automatic smoke generator 10 includes an opening 55 communicating with the interior of the housing 11. A water bafile 56 is mounted in the upper half of the opening to arrest any sparks which may drift upwardly with the products of combustion. The baflle 56 is provided with a continuous stream of water from an elongated trough 57 which feeds the water out of a plurality of perforations to maintain a continuous film of water falling over the baflie 56, and has a cooling effect on the smoke.

Smoke generated in the fire pot 13 is drawn upwardly through'the exhaust stack 58 together with secondary air admitted between the housing 11 and the outer wall 56 and then upwardly out of the exhaust stack 58 for dis tribution to the smoking chamber, rack room or the like.

A flame sensing or heat sensing device is provided in the smoke stack opening 55. The flame sensing device 60 may be responsive to increases in temperature within the housing 11 and/or the presence of open flame and serves to respond to either condition by opening the electrical contacts to terminate operation of the blower 32. On discontinuation of combustion supporting air and continued rotation of the feeder assembly 14, any flames present will generally by snuffed out or smothered, usually on loss of the air supply alone. As a safety precaution, a suitable shower pipe (not shown) may be provided in the top of the housing 11 to douse the flame should the normal means be insufiicient. On cooling of the housing 11 with the extinguishment of the flames, the heat sensing switch 60 closes to energize the blower 32 to supply combustion supporting air to the fire bed to continue generation of smoke.

The operation of the automatic smoke generator of the present invention will now be described. The supply hopper 12 is charged with combustible material such as the wet sawdust 31 illustrated. A fire is kindled in the fire pot 13 and the drive unit 16 is energized as is the blower motor 32. The bed depth measured from the plenum 29 is maintained substantially uniform in a horizontal and vertical direction through the rotation of the feeder assembly 14 which supplies wet sawdust 31 to the combustion area. Throughout rotation of the shaft 20, the vanes 22 and 23 maintain the sawdust in an agitated condition so as to be free flowing into the rotating hopper 38.

A cover 61 may be provided on the top of the rotating hopper 38 to prevent the sawdust from overflowing the upper edges thereof. On each revolution of the shaft 20 the deflecting vane 52 carried by the sleeve-like cylindrical opening 19 pushes a charge of sawdust into the opening 41 in the bottom 39 of the rotating hopper 38. The sawdust falls downwardly along the incline chute 46 towards the bottom of the rotating distributor hopper 42 which releases the same as the bed is burned away. The leading edges 49 and 50 on the plate 43 together with the scraper 48 maintain a bed configuration substantially as shown in cross section in FIG. 1. The trailing edge 51, being slightly lower than the leading edge 49, scrapes off a portion of the sawdust released causing an upward force in the rotating distributor hopper 42 to maintain distribution substantially uniform at all times. As the sawdust 31 builds up in the distributor hopper 42, the differential in edge elevation described above maintains the same agitated slightly by the upward force of the sawdust.

Throughout rotation of the shaft 20 and the feeder assembly 14, air is supplied from the blower 32 to the plenum 29 and out of the ports 30. The rate of combustion of the sawdust 31 can be controlled by adjusting the valve 33 to control the air flow. The spiral scraper 48 directs any material at the center of the fire pot 13 toward the outer edges and assists in maintaining the sawdust bed generally uniform in thickness as measured from the air supply or plenum 29. It is obvious from the foregoing that the generator will produce smoke automatically and continuously once the bed of sawdust is ignited, the supply hopper 12 is maintained full of combustible material, and sufiicient air is supplied to sustain burning.

In some instances, it is desirable to increase or decrease the bed depth to compensate for changes in moisture content of the sawdust, to change the burning rate or the like. In the present invention, this may be conveniently accomplished by releasing the clamp 37 joining the sleeve 36 to the shaft 20, and raising the former upwardly the desired distance. As is well known, an access door (not shown) is provided in the housing 11 to gain access to the fire pot to permit adjustment of the feeder assembly upwardly or downwardly to increase or decrease the depth of the bed of burnable material. As a general rule, once a bed depth and amount of air has been established for a certain type of sawdust, for example, hickory, oak or other hard woods, no further re-adjustrnent is required.

Upon a consideration of the foregoing, it will become obvious to those skilled in the art that various modifications may be made without departing from the invention embodied herein. Therefore, any limitations imposed are to be within the spirit and scope of the appended claims.

I claim:

1. An automatic smoke generator comprising, a fire pot having an annular burning area, a supply hopper positioned above said fire pot and said annular burning area being adapted to be filled with burnable material, an opening in said supply hopper for permitting flow of said material therethrough, an intermediate rotary hopper adapted to receive material from said supply hopper, distributor hopper means in communication with said intermediate rotary hopper, drive means adapted to rotate said intermediate and said distributor hoppers about a central axis, vane means on said supply hopper projecting into said intermediate rotary hopper, said vane means serving to eject material into said distributor hopper on each rotation. thereof, and means associated with the lower edges of said distributor hopper to control the release of material therefrom into said annular burning area, said last named means being positioned within said fire pot and maintaining a uniform depth of burnable material about said axis in said annular burning area to minimize flame-ups and promote cool smoking.

2. The smoke generator of claim 1 wherein scraper means is mounted on said distributor hopper for maintaining said material outwardly of the central axis of rotation.

3. The smoke generator of claim 1 wherein said distributor hopper may be adjusted axially of the axis of rotation to permit adjustment of the total depth of burnable material.

4. In a smoke generator having a fire pot positioned below a supply hopper, an air supply positioned around the lower perimeter of the fire pot, and a bed of combustible material adjacent said air supply, the improvement comprising a feeder means for maintaining said bed at continuous depth to prevent flame ups and obtain optimum generation of smoke, said feeder means comprising a rotating hopper adapted to receive material from said supply hopper, a distributor hopper carried on said rotating hopper and adapted to direct said material from said rotating hopper to said bed of combustible material, vane means projecting into said rotating hopper and adapted to direct material received from said supply hopper outwardly of said rotating hopper on each rotation thereof whereby said combustible material will be directed into said distributor hopper, and means associated with the lower marginal edge of said distributor hopper to maintain said bed at substantially uniform depth thereby to continuously maintain a layer of unburned material over said material undergoing burning, said means associated with the lower edge of said distributor hopper comprising forming the trailing edge of lesser elevation than said leading edge.

5. In a smoke generator having a fire pot positioned below a supply hopper, an air supply positioned around the lower perimeter of the fire pot, and a bed of combustible material adjacent said air supply, the improvement comprising a feeder means for maintaining said bed at continuous depth to prevent flame-ups and obtain optimum generation of smoke, said feeder means comprising a rotating hopper adapted to receive material from said supply hopper, a distributor hopper carried on said rotating hopper and adapted to direct said material from said rotating hopper to said bed of combustible material, vane means projecting into said rotating hopper and adapted to direct material received from said supply hopper outwardly of said rotating hopper on each rotation thereof whereby said combustible material will be directed into said distributor hopper, and means associated with the lower marginal edge of said distributor hopper to maintain said bed at substantially uniform depth thereby to continuously maintain a layer of unburned material over said material undergoing burning, said feeder means including scraper means mounted on said distributor hopper to maintain said material positioned outwardly of the axis of rotation.

6. In combination a smoke generator and a feeder assembly, said smoke generator having an annular burning area and a stationary supply hopper, said feeder assembly being positioned between and maintaining a constant flow of combustible material to said annular burning area, said feeder assembly including a rotating hopper adapted to receive combustible material from said stationary supply hopper, a distributor hopper rotatable with said rotating hopper about an axis and receiving combustible material therefrom, fixed vane means associated with said supply hopper and positioned within said rotating hopper to eject combustible material from said rotating hopper into said distributor hopper on each rotation thereof, and means associated with the lower edges of said distributor hopper to maintain a continuous supply of combustible material in said annular burning area, said last named means being positioned within said fire pot immediately above said annular burning area and being rotatable with said distributor hopper to maintain said combustible material at a preselected and predetermined uniform depth thereby to provide continuous generation of cool smoke while minimizing flame-ups.

References Cited by the Examiner UNITED STATES PATENTS 836,888 11/1906 Parker 214-18 1,811,191 6/1931 Taylor 12659.5 1,939,265 12/1933 Jordan et al 126-595 2,876,762 3/1959 Tipper 12659.5

FOREIGN PATENTS 183,152 6/ 1936 Switzerland.

CHARLES J. MYHRE, Primary Examiner. 

1. AN AUTOMATIC SMOKE GENERATOR COMPRISING, A FIRE POT HAVING AN ANNULAR BURNING AREA, A SUPPLY HOPPER POSITIONED ABOVE SAID FIRE POT AND SAID ANNULAR BURNING AREA BEING ADAPTED TO BE FILLED WITH BURNABLE MATERIAL, AN OPENING IN SAID SUPPLY HOPPER FOR PERMITTING FLOW OF SAID MATERIAL THERETHROUGH, AN INTERMEDIATE ROTARY HOPPER ADAPTED TO RECEIVE MATERIAL FROM SAID SUPPLY HOPPER, DISTRIBUTOR HOPPER MEANS IN COMMUNICATION WITH SAID INTERMEDIATE ROTARY HOPPER, DRIVE MEANS ADAPTED TO ROTATE SAID INTERMEDIATE AND SAID DISTRIBUTOR HOPPERS ABOUT A CENTRAL AXIS, VANE MEANS ON SAID SUPPLY HOPPER PROJECTING INTO SAID INTERMEDIATE ROTARY HOPPER, SAID VANE MEANS SERVING TO EJECT MATERIAL INTO SAID DISTRIBUTOR HOPPER ON EACH ROTATION 